Donald Trump has risen to the top of the Republican presidential candidate ratings while campaigning on the nutty charge that President Obama isn't American, that he is not legally qualified to be president.

The Trump effect has led others, like Sarah Palin, to start hedging their dismissal of these absurdities. If this continues, the Republican race could turn into a race for the muck.

America deserves better. Jobs are short; wages aren't keeping up; home values keep falling. The banks are doing fine, but people are still losing their homes. The rich are paying fewer taxes while the poor pay more fees. The middle class is getting crushed. Good jobs are still shipped abroad, replaced, if at all, by lower-wage work. There is now more student loan debt owed in America than credit card debt.

We need a serious debate about what we do to get out of this hole.

At the federal and state level, furious debates have begun. Conservative legislators and governors are pushing to cut taxes on the rich and on corporations, even as they slash support for schools and health care. With gas rising over $4 a gallon, conservatives return to their "drill, baby, drill" position, while liberals call for accelerating the transition to renewable energy.

We need a vigorous debate about what our strategy is and should be.

Donald Trump made a fortune in real estate. He presumably would have much to say about how we deal with our debt, handle the continuing housing crisis, or develop a high-end manufacturing strategy that works. He likely has serious views about energy policy, and certainly about whether we should raise or lower taxes on the wealthy.

Instead of entering that debate, he's riding a toxic wave by emitting poisonous charges he must know are not true. This nonsense about Obama's birth is one of various efforts to label him as un-American, as alien. Some say he's not a Christian, but a Muslim. Mike Huckabee muses on the Kenyan socialism Obama must have imbibed while growing up in Kenya, where he never lived.

This is an old and tawdry game. When Dr. King was challenging segregation, Southerners knew they couldn't win the argument with him on equal rights or the right to vote. So they labeled him a communist. They said he was an outside agitator, even though his church was in Georgia. When he spoke out against Vietnam, they debated not his views, but his qualification even to have an opinion. He was a preacher, they scorned, not a foreign-policy expert, even though the experts got us into the debacle. For King, as for Obama, all this was simply a diversion, a way not to debate his ideas or his positions, but to dismiss them from consideration by slurring the messenger.

America's politics are bare-knuckled. Politicians understand that their personal lives, their finances, the slips of tongue they make at the end of hard days are all grist for the debate. At best, parts of the media offer analysis of the truthfulness of various charges--but that analysis never has the reach of the original slurs or lies.

In the end, voters decide what kind of debate they will have. If they reward candidates for running below-the-belt campaigns rife with lies and slurs, more candidates will adopt those tactics.

Donald Trump is peddling a discrediting slur about the president that challenges the president's core integrity and raises unnecessary doubt and fear by making him the object of deception and dishonesty.

Legitimate economic anxiety and frustration must not be turned into toxic anger and ugliness.

I know Donald Trump. He is a better man than this.

If he dares to lead, let him call upon our better angels of hope. Leaders who lead us the best take us from the guttermost to the uttermost. Donald Trump must use his considerable skills to uplift our nation, not divide it.

We now know Donald Trump is happy to peddle a lie about America's president. We know virtually nothing about his views on America's course forward. This discrediting code language about the president's birthplace, religion and qualifications is a debase argument and a disservice to Trump and the country.